Abstract

Aims

Accurate selection of patients with left bundle branch block (LBBB) may help increasing response to cardiac resynchronization therapy (CRT). There is no agreement on LBBB definition. The aim of the study was to investigate the prevalence of ‘true-LBBB’ according to Strauss in patients undergoing CRT.

Methods and results

The study population included 414 consecutive patients (71.9% men; mean age 69.7 ± 9.6 years), who underwent CRT according to 2010 European Society of Cardiology (ESC) guidelines. Patients were classified into three groups: traditional LBBB according to American Heart Association, LBBB according to Strauss and intraventricular conduction delay (IVCD). Subsequently, they were re-classified into classes of recommendations, according to the current 2013 ESC Guidelines. Traditional LBBB was recorded in 229 patients (55%), an LBBB according to Strauss in 153 (37%) and an IVCD in 32 (8%). Patients with an LBBB according to Strauss showed a significantly more prolonged QRS duration (P Conclusions

Applying stricter criteria, only 37% of patients undergoing CRT showed a true-LBBB according to Strauss. Accurate identification of true-LBBB may have a potential additional value in better selecting patients.